• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.1
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• pp.25-35
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• 2018

This study presents microstructural characteristics and strength properties of alkali-activated kaolin(K)-fly ash(FA) blends binders. The compressive strength, X-ray diffraction(XRD), thermogravimetric(TG) analysis and SEM/EDS were measured for hardened samples. The results were shown that all the samples had developed the compressive strength over time, regardless of replacement levels of K. It was found that when the amount of K increased, the strengths of samples decreased. In XRD result, no new crystalline phases were observed in all the hardened samples other than the crystalline components of raw FA and K, whereas TG analysis showed that N-A-S-H gel was formed as a reaction product in all the samples. Samples did not have the typical microstructure of dense, and there is little significant difference between the microstructures of the samples despite the differences in the strength testing results with replacement ratios of K. This study showed that the strength of sample was larger for lower Si/Al ratio of reaction product formed in sample. According to the correlation between Si/Al ratio and strength in this study, it is expected that if a chemical additive is used for lowering the Si/Al ratio of reaction product(i.e., increasing the $Al_2O_3$ solubility) in alkali-activated K-FA blends binders, strength improvement in K-FA blends binders could be achieved.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.1
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• pp.57-65
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• 2005

This study was performed to investigate the effects of very low calorie diet (VLCD) using meal replacements that contain the wild grass extracts that are consisted of mainly Samul-tang ingredients on weight reduction and health promotion in the obese women (BMI$\geq$25 kg/$m^2$) for four weeks. Fifty six premenopausal women participated in this experiment. Each subject was either classified as part of the control group (C group, n=28) that consumed 3 regular meals a day or the meal replacement group (MR group, n=28) that consumed 1 regular meal and 2 meal replacements within 600 kcal/day. Anthropometric measurements, body composition, health related factors, and psychological factors were assessed before (the initial) and after (the 4$^{th}$ week) the study. Obesity was significantly decreased after the diet intervention. Anthropometric measurements such as weight, waist and hip circumference, and BMI and body composition such as body fat, and fat mass were significantly decreased in all groups after the diet intervention. Anthropometric measurements and body composition of the MR group were significantly decreased more than those of the C group. Serum total cholesterol was significantly decreased in the MR groups but not in the C group and serum triglyceride concentration was significantly decreased in all groups after the diet intervention. All the biochemical measurements were within normal ranges after the diet intervention. Psychological factors such as stress and depression were significantly decreased in two groups after the diet intervention. Therefore, VLCD using meal replacements is very effective for weight reduction in the obese premenopausal women.

• The korean journal of orthodontics
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• v.34 no.4 s.105
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• pp.333-342
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• 2004

The purpose of this study was to evaluate the clinical effectiveness of a plasma arc light and light emitting diode (LED), compared with shear bond strength and the failure pattern of brackets bonded with visible light in direct bonding. Brackets were bonded with Transbond XT to 60 human premolars embedded in the resin blocks according to different light-curing methods. Then, the shear bond strength of each group was measured using a universal testing machine (Instron) and the adhesive failure pattern after debonding was visually examined by light microscope. The results were as follows: 1. The shear bond strength showed no significant difference between the visible light and light emitting diode, but the plasma arc light exhibited a significantly lower shear bond strength compared with the visible light and light emitting diode. 2. In the visible light and light emitting diode, adhesive failure patterns were similar. Bond failure occurred more frequently at the enamel-adhesive interface. 3. The bonding failure of brackets bonded with plasma arc light occurred more frequently at the bracket-adhesive interface. The results of this study suggest that plasma arc light, light emitting diode and visible light are all clinically useful in the direct bonding of orthodontic brackets.

• The Journal of Korean Academy of Prosthodontics
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• v.55 no.2
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• pp.151-155
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• 2017

Purpose: The aim of this study was to evaluate screw removal torque of the two-piece zirconia abutment with the novel titanium component compared to the conventional one-piece titanium abutment in the internal connection implant before and after dynamic cyclic loading. Materials and methods: Two types of the abutment assemblies with internal connection were prepared and divided into the groups; titanium abutment-titanium abutment screw assemblies as control, and zirconia abutment-titanium socket-titanium abutment screw assemblies as experimental group. A total of 12 abutments and implants were used of six assemblies each group. Each assembly was tightened to 30 Ncm. A cyclic load of 300 N at an angle of 30 degrees in reference to the loading axis was applied until one million cycles or failure. The removal torque values (RTVs) of the abutment screws were measured with a digital torque gauge before and after cyclic loading. The RTVs of the pre load and post load were analyzed with t-test, and P-values < .05 were considered statistically significant. Results: The assemblies of both groups survived all after the dynamic cyclic loading test without screw loosening. The statistically significant differences were found between the mean RTVs before and after the cyclic loading in both groups (P < .05). The RTV differences for the control and the experimental group were $-7.25{\pm}1.50Ncm$ and $-7.33{\pm}0.93Ncm$, respectively. Statistical analysis revealed that the RTV differences in both groups were not significantly different from each other (P > .05). Conclusion: Within the limitation of this study, the two-piece zirconia abutment with the titanium component did not show a significant RTV difference of the abutment screw compared to the titanium abutment after dynamic cyclic loading.

• Journal of the korean academy of Pediatric Dentistry
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• v.45 no.3
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• pp.370-377
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• 2018

Although the frequency of composite resin restoration in children is gradually increasing, there are insufficient researches about the rate of composite resin repair in children. The purpose of this study was to evaluate the repair rate of composite resin restorations in the permanent first molar in children under 12 years old. This study retrospectively analyzed 169 children treated with composite resin restoration in the permanent first molar from May 2014 to April 2015. According to the location of the tooth, the repair rate was higher in the mandible than maxilla and in the left than right. In the classification of restoration, the repair rate was the highest in the class II cavity, and the repair rate was the lowest in the restoration of the occlusal surface only. Repair rate in two years was 14.8%, and repair hazard ratio decreased with age. The most common reason of composite resin restoration replacement was the secondary caries (74.1%). Within the limits of study, the repair rate of children was higher than that of adult due to the characteristics of children. Therefore, dentists should understand these characteristics and try to reduce the repair rate of composite resin composite restorations.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.5
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• pp.717-722
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• 2016

The purpose of this study was to evaluate the quality of madeleine added with different concentrations (0, 1, 3, 5, and 7%) of organic ginseng leaves. The study results found that the pH and moisture of madeleine with control were higher than those of the samples. On the other hand, specific gravity of madeleine was highest at 7% leaf content (1.04). The loss rate of madeleine was not significantly different among the samples. The Hunter L, a, and b values of crust decreased as the concentration of organic ginseng leaves increased. The Hunter L and a values of crumb decreased as the concentration of organic ginseng leaves increased, whereas b values of crumb increased. The hardness of madeleine increased after addition of organic ginseng leaves, whereas adhesiveness, chewiness, gumminess, and cohesiveness of madeleine decreased. 2,2'-Diphenyl-1-picrylhydrazyl radical scavenging activity of madeleine was significantly elevated with increasing content of organic ginseng leaves (P<0.05). In a sensory evaluation, healthy image and color were highest at 3% leaf content, whereas moistness, softness, and chewiness decreased as the concentration of organic ginseng leaves increased. The flavor and overall acceptability of madeleine added with 3% organic ginseng leaves were higher than those of both control and other samples. Therefore, the results suggest that 3% organic ginseng leaves addition to madeleine could be helpful for improving physical quality and taste.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.2
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• pp.229-234
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• 2011

This study investigated quality characteristics of 4 year-old ginseng by enzymatic hydrolysis conditions to increase utilization. Ginseng was ground after steaming and was each treated with hydrolase A, B, C and D. When quality characteristics by the enzymes were examined, no significant difference was observed with pH of 5.5~5.6 and the sugar content of 4.0~4.33. The crude saponin content was the highest in ginseng treated with D, followed by B, C and A. The crude saponin, the reducing sugar and the total sugar contents increased until 0.3% (w/w) concentration in enzyme D with no significant difference by its concentration. Although active ingredients increased with time passage of hydrolysis, no significant change was found after three hours and the crude saponin content was the highest when ginseng was treated at $60^{\circ}C$. From these results, optimum conditions for 4 year-old ginseng were $60^{\circ}C$ for 3 hours with 0.3% (w/w) enzyme D, and under these conditions the reducing sugar, the total sugar and the crude saponin contents recorded 18.11, 36.21 and 4.23 mg/g, respectively. Therefore, enzymatic hydrolysis was found to be effective in increasing active ingredients of 4 year-old ginseng with various usages expected.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.3
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• pp.410-414
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• 2013

Styela (S.) clava (Korean name: miduduk) tunic is produced as a by-product after processing of S. clava. For utilizing this tunic, a konjac containing the tunic extracts was prepared and the qualities evaluated for their color, textural properties, and sensory attributes. The tunic extract was prepared by boiling tunic with water, followed by filtration through filter paper. Significant 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging activity was found in the tunic extract. Increasing the concentration of tunic extract in the konjac tended to decrease lightness (L) and increase the redness (a) and the yellowness (b) of the konjac. The strength and hardness of the konjac increased with increasing concentrations of the tunic extract. All test samples with a 3 mm thickness had good flexibility and did not break even after 4 times folds. In sensory evaluations, the konjac containing 25% S. clava tunic extracts acquired a relatively higher score. The results suggest that S. clava tunic can be applied to konjac products to improve their quality and functionality.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.3
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• pp.334-339
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• 1983

With the 91 lines of Italian millet collected throughout the whole country in Korea and the 238 varieties from several Asian countries, trial was carried out to elucidate its differentiation, dissemination and distribution, and the ethnobotanical relations to the adjacent area. Glutinous millets which consisted of 66% among the collected Korean lines were widely distributed throughout the whole country, but non-glutinous ones were mainly distributed in the mountainous regions and Jeju island. The variations in germinability at low temperature were recognized among lines, but seemed not to be closely related to their regional distribution. The collected lines with small grain size were distributed mainly in the mountainous regions of middle and northern part of Korea and larger ones in Jeonnam province and Jeju island. And some of them were larger in grain size as compared with that of Japanese and Republic of China varieties. Seed coat color of collected lines in Korea showed wide variations from yellow to gray, especially in Gyungbuk province. However, all lines from Chungnam, Jeonnam and Gyungnam province were yellow in seed coat color. All lines from Korean collection except two lines indicated negative(-) phenol reaction which is very similar to that of Japan and China, while these were quite different from the varieties of Republic of China, Philippines and India, of which 30-60% showed positive(+) phenol reaction. The pattern of the esterase isozyme m Korean lines was simillar to that of Japanese lines and this was quite different from that of Republic of China, Philippines and India. Variation of this trait was greater in Chinese and Korean lines.

• Korean journal of food and cookery science
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• v.13 no.2
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• pp.204-212
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• 1997

The characteristics of sponge cakes prepared with replacement of 30, 50, 75, or 100% of sucrose with isomaltooligosaccharide (IOS), fructooligosanharide (FOS), maltitol symp (MS), or maltitol powder (MP), were examined through physical measurement and sensory evaluation. The specific gravities of foams and cake batters were not significantly different among samples (p .0.05). The use of IOS increased the viscosity of cake batter. The cakes containing IOS, FOS, MS, or MP were softer than control cakes (sucrose 100%). Especially cakes prepared with 30, 50％ IOS, or 75, 100％ MP, appeared to be fragile. When increasing levels of IOS or FOS were incorporated in the cake formula, cake crust color was getting darker than that of control cake, whereas cake containing maltitol was getting lighter as the levels of replacement increased. Generally, the volume of cake containing FOS were superior to that of control cake, whereas those of cakes containing above 50% MP were inferior. Sensory analysis of experimental cakes did not show significant differences from the control cake for softness, springiness and gumminess. Sweetness increased replacing the sucrose with FOS, MS or MP (30, 50%) and moistness increased using IOS, FOS, MS, or MP without agreement with moisture contents of cakes. Replacement of 30, 50% sucrose with MS or 30％ with MP did not affect greatly the physical measurements or sensory characteristics studied.